package cn.zysheep.gateway.config;

import com.alibaba.csp.sentinel.adapter.gateway.common.SentinelGatewayConstants;
import com.alibaba.csp.sentinel.adapter.gateway.common.api.ApiDefinition;
import com.alibaba.csp.sentinel.adapter.gateway.common.api.ApiPathPredicateItem;
import com.alibaba.csp.sentinel.adapter.gateway.common.api.ApiPredicateItem;
import com.alibaba.csp.sentinel.adapter.gateway.common.api.GatewayApiDefinitionManager;
import com.alibaba.csp.sentinel.adapter.gateway.common.rule.GatewayFlowRule;
import com.alibaba.csp.sentinel.adapter.gateway.common.rule.GatewayParamFlowItem;
import com.alibaba.csp.sentinel.adapter.gateway.common.rule.GatewayRuleManager;
import com.alibaba.csp.sentinel.adapter.gateway.sc.SentinelGatewayFilter;
import com.alibaba.csp.sentinel.adapter.gateway.sc.callback.BlockRequestHandler;
import com.alibaba.csp.sentinel.adapter.gateway.sc.callback.GatewayCallbackManager;
import com.alibaba.csp.sentinel.adapter.gateway.sc.exception.SentinelGatewayBlockExceptionHandler;
import org.springframework.beans.factory.ObjectProvider;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.codec.ServerCodecConfigurer;
import org.springframework.web.reactive.function.BodyInserters;
import org.springframework.web.reactive.function.server.ServerResponse;
import org.springframework.web.reactive.result.view.ViewResolver;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;

import javax.annotation.PostConstruct;
import java.util.*;

/**
 * @version v1.0
 * @Author: lyw
 * @Date: 2021/8/18
 */
@Configuration
public class GatewayConfiguration {
    private final List<ViewResolver> viewResolvers;
    private final ServerCodecConfigurer serverCodecConfigurer;

    public GatewayConfiguration(ObjectProvider<List<ViewResolver>> viewResolversProvider,
                                ServerCodecConfigurer serverCodecConfigurer) {
        this.viewResolvers = viewResolversProvider.getIfAvailable(Collections::emptyList);
        this.serverCodecConfigurer = serverCodecConfigurer;
    }

    /***
     * 配置限流的异常处理器:SentinelGatewayBlockExceptionHandler
     * */
    @Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public SentinelGatewayBlockExceptionHandler sentinelGatewayBlockExceptionHandler() {
        return new SentinelGatewayBlockExceptionHandler(viewResolvers, serverCodecConfigurer);
    }

    /***
     * 配置限流过滤器
     * */
    @Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public GlobalFilter sentinelGatewayFilter() {
        return new SentinelGatewayFilter();
    }

    /***
     * 配置初始化的限流参数
     * */
//    @PostConstruct
//    public void initGatewayRules() {
//        Set<GatewayFlowRule> rules = new HashSet<>();
//        rules.add( new GatewayFlowRule("user-service") //资源名称
//                .setCount(1) // 限流阈值
//                .setIntervalSec(1) // 统计时间窗口，单位是秒，默认是 1 秒
//                .setParamItem(new GatewayParamFlowItem().setParseStrategy(
//                        SentinelGatewayConstants.PARAM_PARSE_STRATEGY_URL_PARAM).setFieldName("id"))
//                );
//        GatewayRuleManager.loadRules(rules);
//    }

    @PostConstruct
    public void initGatewayRules(){
        Set<GatewayFlowRule> rules = new HashSet<>();
        rules.add(new GatewayFlowRule("order_api").setCount(1).setIntervalSec(1));
        rules.add(new GatewayFlowRule("user_api").setCount(1).setIntervalSec(1));
        GatewayRuleManager.loadRules(rules);
    }

    //自定义限流异常页面
    @PostConstruct
    public void initBlockHandlers(){
        BlockRequestHandler blockRequestHandler = new BlockRequestHandler() {
            @Override
            public Mono<ServerResponse> handleRequest(ServerWebExchange serverWebExchange, Throwable throwable) {
                Map map = new HashMap();
                map.put("code",001);
                map.put("msg","对不起,接口被限流了");
                return ServerResponse.status(HttpStatus.OK)
                        .contentType(MediaType.APPLICATION_JSON_UTF8)
                        .body(BodyInserters.fromObject(map));
            }
        };
        GatewayCallbackManager.setBlockHandler(blockRequestHandler);
    }

    //自定义API分组
    @PostConstruct
    private void initCustomizedApis(){
        Set<ApiDefinition> definitions = new HashSet<>();
        ApiDefinition api1 = new ApiDefinition("order_api")  //apiName自定义
                .setPredicateItems(new HashSet<ApiPredicateItem>(){{
                    // 以/order/**  /order开头的请求执行限流
                    add(new ApiPathPredicateItem().setPattern("/order-service/order/**")  // /order-service注册中心读取的服务名
                            .setMatchStrategy(SentinelGatewayConstants.URL_MATCH_STRATEGY_PREFIX));
                }});
        ApiDefinition api2 = new ApiDefinition("user_api")
                .setPredicateItems(new HashSet<ApiPredicateItem>(){{
                    // /user/saveUser 完整的url路径匹配执行限流
                    add(new ApiPathPredicateItem().setPattern("/user-service/user/saveUser"));; // /user-service注册中心读取的服务名
                }});
        definitions.add(api1);
        definitions.add(api2);
        GatewayApiDefinitionManager.loadApiDefinitions(definitions);
    }
}
